Brushless electric motors or electronically commutated electric motors gain significance at an increasing rate. They replace in particular electric motors equipped with brushes in many technical applications. The advantages over motors equipped with brushes involve above all low efforts in maintenance because there is no need for commutator brushes exposed to wear and there is principally a higher efficiency due to the omission of commutator losses caused by brush contact resistances. In addition, functions can be realized in conjunction with ‘intelligent’ electronic commutation devices that are not possible with brush-fitted motors or can be reached only with major additional mechanical efforts. This additional effort relates to the operation in the zone of weak fields or in the field weakening mode and the realization of a very low waviness of the drive torque.
As the functions of mechanical, inherently much safer and more reliable components (in this case the commutator brushes of a commutator motor) are replaced by mechatronic assemblies in brushless electric motors, appropriate measures must safeguard the fail-safety. A comparatively large number of possible errors are caused due to the relatively high complexity of the commutation electronics.
Reliable error detection is necessary especially for safety-critical applications of electronically commutated electric motors.